code review 2450041: freetype: add NewAlpha{Src,Over}Painter constructor fun...

freetype: add NewAlpha{Src,Over}Painter constructor function for
consistency with existing NewFooPainter functions.

Unbreak build from ColorImage change in the core image package.

[nigeltao, 2010-10-12 03:45:46]

Hello adg (cc: golang-dev@googlegroups.com),

I'd like you to review this change.

[adg, 2010-10-12 05:06:27]

LGTM

On 12 October 2010 14:45,  <nigeltao@golang.org> wrote:
> Reviewers: adg,
>
> Message:
> Hello adg (cc: golang-dev@googlegroups.com),
>
> I'd like you to review this change.
>
>
> Description:
> freetype: add NewAlpha{Src,Over}Painter constructor function for
> consistency with existing NewFooPainter functions.
>
> Unbreak build from ColorImage change in the core image package.
>
> Please review this at http://codereview.appspot.com/2450041/
>
> Affected files:
>  M example/gamma/main.go
>  M example/raster/main.go
>  M freetype/freetype.go
>  M freetype/raster/paint.go
>
>
> Index: example/gamma/main.go
> ===================================================================
> --- a/example/gamma/main.go
> +++ b/example/gamma/main.go
> @@ -54,8 +54,7 @@
>        draw.Draw(rgba, image.Rect(0, 0, w, h/2), image.Black, image.ZP)
>        draw.Draw(rgba, image.Rect(0, h/2, w, h), image.White, image.ZP)
>        mask := image.NewAlpha(50, 50)
> -       painter := raster.NewAlphaPainter(mask)
> -       painter.Op = draw.Src
> +       painter := raster.NewAlphaSrcPainter(mask)
>        gammas := []float{1.0 / 10.0, 1.0 / 3.0, 1.0 / 2.0, 2.0 / 3.0, 4.0 /
> 5.0, 1.0, 5.0 / 4.0, 3.0 / 2.0, 2.0, 3.0, 10.0}
>        for i, g := range gammas {
>                clear(mask)
> Index: example/raster/main.go
> ===================================================================
> --- a/example/raster/main.go
> +++ b/example/raster/main.go
> @@ -141,13 +141,12 @@
>        contour(r, outside)
>        contour(r, inside)
>        mask := image.NewAlpha(w, h)
> -       p := raster.NewAlphaPainter(mask)
> -       p.Op = draw.Src
> +       p := raster.NewAlphaSrcPainter(mask)
>        r.Rasterize(p)
>
>        // Draw the mask image (in gray) onto an RGBA image.
>        rgba := image.NewRGBA(w, h)
> -       gray := image.ColorImage{image.AlphaColor{0x1f}}
> +       gray := image.NewColorImage(image.AlphaColor{0x1f})
>        draw.Draw(rgba, rgba.Bounds(), image.Black, image.ZP)
>        draw.DrawMask(rgba, rgba.Bounds(), gray, image.ZP, mask, image.ZP,
> draw.Over)
>        showNodes(rgba, outside)
> Index: freetype/freetype.go
> ===================================================================
> --- a/freetype/freetype.go
> +++ b/freetype/freetype.go
> @@ -178,7 +178,7 @@
>                e0 = e1
>        }
>        a := image.NewAlpha(xmax-xmin, ymax-ymin)
> -       c.r.Rasterize(raster.AlphaSrcPainter{a})
> +       c.r.Rasterize(raster.NewAlphaSrcPainter(a))
>        return a, image.Point{xmin, ymin}, nil
>  }
>
> Index: freetype/raster/paint.go
> ===================================================================
> --- a/freetype/raster/paint.go
> +++ b/freetype/raster/paint.go
> @@ -69,6 +69,11 @@
>        }
>  }
>
> +// NewAlphaOverPainter creates a new AlphaOverPainter for the given image.
> +func NewAlphaOverPainter(m *image.Alpha) AlphaOverPainter {
> +       return AlphaOverPainter{m}
> +}
> +
>  // An AlphaSrcPainter is a Painter that paints Spans onto an image.Alpha
>  // using the Src Porter-Duff composition operator.
>  type AlphaSrcPainter struct {
> @@ -103,6 +108,11 @@
>        }
>  }
>
> +// NewAlphaSrcPainter creates a new AlphaSrcPainter for the given image.
> +func NewAlphaSrcPainter(m *image.Alpha) AlphaSrcPainter {
> +       return AlphaSrcPainter{m}
> +}
> +
>  type RGBAPainter struct {
>        // The image to compose onto.
>        Image *image.RGBA
>
>
>

[nigeltao, 2010-10-12 05:55:11]

*** Submitted as
http://code.google.com/p/freetype-go/source/detail?r=76351bb9d3b8 ***

freetype: add NewAlpha{Src,Over}Painter constructor function for
consistency with existing NewFooPainter functions.

Unbreak build from ColorImage change in the core image package.

R=adg
CC=golang-dev
http://codereview.appspot.com/2450041